The Swift code base uses something similar that the core team wrote: GYB, Generate Your Boilerplate. It’s used to generate several variants of similar code that

The Swift code base uses something similar that the core team wrote: GYB, Generate Your Boilerplate. It’s used to generate several variants of similar code that would be cumbersome to maintain otherwise. https://github.com/apple/swift/blob/master/utils/gyb.py https://github.com/apple/swift/blob/master/utils/gyb.py